Smith is of predominantly British descent through his father Davey Boy Smith who was from Lancashire, England and his mother Diana Hart who belongs to a large family of Ulster Scot and Irish heritage. Smith also has Greek ancestry through a maternal great-grandmother.[14] He has a sister, voice over artist Georgia Smith.[15][16] He is very good friends with TJ Wilson and his cousin Teddy Hart, and used to live with Wilson.[16][17] Smith is also close friends with his cousin Nattie Neidhart, and the two lived together as children while their fathers were wrestling as a team.[18]

Smith began wrestling at the age of eight,[1] he was trained by his father Davey Boy Smith and uncle Bruce Hart.[9] He made an early appearance with World Wrestling Entertainment (WWE) on October 5, 1996 at the age of 11 when he teamed with his cousin Ted Annis against TJ Wilson and Andrew Picarnia at a WWE house show in Calgary.[1] He also appeared at the conclusion of In Your House 16: Canadian Stampede with the rest of the Hart family.[19] He made his professional debut at the age of fifteen at the Rockyford Rodeo, and went on to become a mainstay of the Calgary-based Stampede Wrestlingpromotion. In May 2002, Smith teamed with his father on two occasions, shortly before his father died.[1] Smith was offered a contract with World Wrestling Entertainment in the summer of 2004, but opted to attend college and wrestle in Japan before signing.[1][20]

In January 2005, Smith went on a five-week tour of Japan, wrestling with New Japan Pro Wrestling as "Black Assassin" and suffered a broken hand in the process.[3][1] Later that year, Smith left Stampede Wrestling and wrestled several dark matches for World Wrestling Entertainment (WWE),[1] before embarking upon a second tour of Japan. He returned to Stampede Wrestling in October 2005, and on November 25, 2005 was defeated by T.J. Wilson in the finals of a tournament for the vacant North American Heavyweight Championship.[1]

On October 16, Smith lost the FCW Southern Heavyweight Championship to Afa Jr.[29][35] He was unable to make the referee's ten count and was counted out, due to being in the United Kingdom with WWE.[35]

In mid-2006, Smith appeared on Raw, despite not being part of the main roster, in a segment where he and others in the locker room chased away ECW invaders. He then was not seen again on the main roster in over a year.[36]

He made his television debut as "DH Smith" on the October 22, 2007 episode of Raw, defeating Carlito using his father's trademark running powerslam.[37][38] He dedicated the match to his father.[37] On October 29, Smith and Jeff Hardy defeated Carlito and Mr. Kennedy.[39]

On April 15, 2009, Smith was drafted to the ECW brand as part of the 2009 Supplemental Draft, without making any appearances on SmackDown.[49] Smith made his ECW debut on May 12, as a villain, attacking Finlay during Finlay's match with Tyson Kidd (TJ Wilson), using the name David Hart Smith.[7] Smith, Kidd and Natalya formed a new version of The Hart Foundation, named The Hart Trilogy at first, although on the May 27 episode of ECW, the name was tweaked to The Hart Dynasty.[50][51] Smith was victorious in his first match for ECW, defeating Finlay on the May 19 episode, with help from Kidd and Natalya.[50]

After a failed attempt to regain the championship, in which Kidd was pushed off balance during their double-team Hart Attack move, Kidd and Smith began to have a falling out with one another. This culminated on the November 15 episode of Raw, when Kidd refused to tag in and attacked Smith during a match for the WWE Tag Team Championship against The Nexus (Justin Gabriel and Heath Slater).[68] ending their partnership. On the December 2 episode of WWE Superstars, Smith beat Kidd in a singles match. Afterward, Smith offered to shake Kidd's hand, but Kidd slapped him across the face.[69] On the next episode of Raw, Kidd defeated Smith in a rematch.[70]

"When I was in WWE I lost the passion and when I left WWE, I thought that my career was done."

After losing to Kidd, Smith would be restricted to appearing on Superstars, mostly participating in tag team matches with Yoshi Tatsu or Darren Young.[72] Smith's last match was on the April 28 edition of Superstars, where he lost to Zack Ryder.[73] After months of inactivity, Smith was released from his contract with WWE on August 5, 2011. The following week on RawCM Punk mentioned Smith being released from WWE.[74] Smith announced on his Facebook that he would be going to wrestle in Japan.[75]

On August 20, 2011, Smith, working under his real name, made his return to the independent circuit defeating Dan Maff at Pro Wrestling Syndicate.[76] On August 27, 2011, Smith, working under his real name, made his debut for Japanese Inoki Genome Federation (IGF), losing to Hideki Suzuki. On September 3, he teamed with Bobby Lashley in a losing effort against Kendo Kashin and Kazuyuki Fujita. On November 6, Smith wrestled in the main event of a Stampede Wrestling show in Barrie, Ontario,[77] defeating Fit Finlay.[78] In early December, Smith defeated Jason Styles and Ryan Von Kool to become the BTW Heavyweight Champion and lost it in March to Ryan Von Kool.On November 25, 2011, Smith debuted for Billy Corgan's Resistance Pro Wrestling and took on Kevin Steen in the semi final of RPW Heavyweight Championship tournament, the match ended in a time limit draw and therefore both progressed to the finals of the tournament.

On January 13, 2012, Smith defeated The Almighty Sheik and Kevin Steen to become the first Heavyweight Champion of Resistance Pro Wrestling promotion.[5][82] Over the next few months, Smith would take on Rhino in various matches culminating on May 11, in a steel cage match with special referee Raven which once again Smith would win.[83] However, the title was stripped on October 14, 2012.[84]

April 2012, Smith made an appearance for Dynamite Championship Wrestling in Delaware competing in their Annual Honor Cup Tournament. Smith also made a second appearance at their May show, Overdrive, teaming with Zac "The Ripper" Conner against Mark "The Dragonfly" Harro and "The Mapleleaf Machine" Kao Storm (Octane).

NWA Florida Underground Wrestling brought in Smith to take on top star Kennedy Kendrick on May 25, 2013 at ThrowDown 3 defeating Kendrick by DQ. Since Smith's debut he has traded wins with Kendrick with neither man gaining the edge until Smith announced Jim "Anvil" Neidhart would come in and team with him at Silver Screen Showdown on September 20, 2013 which saw Smith and Neidhart defeat Kendrick and his bodyguard Deimos.

On August 13, 2012, New Japan Pro Wrestling announced that Smith would be returning to the promotion the following month as a member of Minoru Suzuki's Suzuki-gun stable, forming a regular tag team with stablemate Lance Archer.[85][86] Smith said that New Japan wanted a huge monster as Archer's partner. Also, he received a good offer from All Japan Pro Wrestling, but he chose NJPW due to the previous relationship.[71] Smith wrestled his return match on September 7, when he, Lance Archer, Minoru Suzuki and Taka Michinoku were defeated in an eight-man tag team match by Hiroyoshi Tenzan, Satoshi Kojima, Togi Makabe and Yuji Nagata, following a disqualification.[87] On September 9, Smith submitted IWGP Tag Team Champion Hiroyoshi Tenzan in another eight man tag team match, after which he and Archer, dubbing themselves K.E.S. (Killer Elite Squad), made a challenge for his and Satoshi Kojima's title.[88] On September 24, New Japan renamed Smith "Davey Boy Smith Jr.".[6][89] On October 8 at King of Pro-Wrestling, K.E.S. defeated Kojima and Tenzan to win the IWGP Tag Team Championship.[90][91] K.E.S. made their first successful title defense on November 11 at Power Struggle, defeating Tenzan and Kojima in a rematch.[92][93] From November 20 to December 1, K.E.S. took part in the round-robin portion of the 2012 World Tag League, finishing with a record of four wins and two losses, advancing to the semifinals of the tournament in the second place in their group.[94][95] On December 2, K.E.S. defeated Always Hypers (Togi Makabe and Wataru Inoue) to advance to the finals of the tournament.[96] Later that same day, K.E.S. was defeated in the finals of the 2012 World Tag League by Sword & Guns (Hirooki Goto and Karl Anderson).[96] On January 4, 2013, at Wrestle Kingdom 7 in Tokyo Dome, K.E.S. defeated Sword & Guns in a rematch to retain the IWGP Tag Team Championship.[97][98] On February 10 at The New Beginning, Smith and Archer defeated Tenzan and Kojima for their third successful defense of the IWGP Tag Team Championship.[99] On March 11, Smith entered the 2013 New Japan Cup, defeating IWGP Intercontinental ChampionShinsuke Nakamura in his first round match.[100] Smith's main event win over the former three-time IWGP Heavyweight Champion was referred to as the biggest of his career.[101] Six days later, Smith advanced to the semifinals of the tournament with a win over Yujiro Takahashi.[102] On March 23, Smith was eliminated from the tournament in the semifinals by Hirooki Goto.[103] On April 5, Smith and Archer made their fourth successful defense of the IWGP Tag Team Championship against Shinsuke Nakamura and Tomohiro Ishii.[104] Two days later at Invasion Attack, Smith unsuccessfully challenged Nakamura for the IWGP Intercontinental Championship.[105][106] On April 20, Smith and Archer defeated Ryan Genesis and Scot Summers in Houston, Texas to not only retain the IWGP Tag Team Championship, but to also win the NWA World Tag Team Championship.[107] On May 3 at Wrestling Dontaku 2013, K.E.S. lost the IWGP Tag Team Championship back to Tencozy in a four-way match, which also included Takashi Iizuka and Toru Yano, and Manabu Nakanishi and Strong Man, though neither Smith nor Archer was involved in the finish.[108][109] K.E.S. received a rematch for the title on June 22 at Dominion 6.22 in a three-way match, which also included Iizuka and Yano, but were unable to regain the title, when Kojima pinned Archer for the win.[110][111] On August 1, Smith entered the 2013 G1 Climax.[112] The tournament concluded on August 11 with a match, where Smith was defeated by his tag team partner Lance Archer, costing him a spot in the finals and ending his tournament with a record of five wins and four losses.[113][114]

Smith in June 2014

On November 9 at Power Struggle, K.E.S. faced Tencozy and The IronGodz (Jax Dane and Rob Conway) in a two-fall three-way match. In the first fall, they lost the NWA World Tag Team Championship to Dane and Conway, but came back in the second to defeat Tencozy for the IWGP Tag Team Championship.[115][116] From November 24 to December 8, K.E.S. took part in the 2013 World Tag League.[117] After winning their round-robin block with a record of five wins and one loss,[118] they were eliminated from the tournament in the semifinals by their old rivals, Tencozy.[119] On January 4, 2014, at Wrestle Kingdom 8 in Tokyo Dome, K.E.S. lost the IWGP Tag Team Championship to the winners of the tournament, Bullet Club (Doc Gallows and Karl Anderson).[120][121] K.E.S. received a rematch for the title on February 9 at The New Beginning in Hiroshima, but were again defeated by Bullet Club.[122][123] On May 25 at Back to the Yokohama Arena, K.E.S. failed to regain the NWA World Tag Team Championship from Tencozy in a three-way match, which also included Rob Conway and Wes Brisco.[124] On June 21 at Dominion 6.21, K.E.S. received another shot at the NWA World Tag Team Championship, this time in a regular tag team match, but were again defeated by Tencozy.[125] From July 23 to August 8, Smith took part in the 2014 G1 Climax, where he finished eighth out of the eleven wrestlers in his block with a record of five wins and five losses, scoring a big win over Hiroshi Tanahashi on the final day.[126][127] On October 13 at King of Pro-Wrestling, K.E.S. defeated Tencozy to regain the NWA World Tag Team Championship.[128][129] From November 22 to December 5, K.E.S. took part in the 2014 World Tag League.[130] The team finished their block with a record of four wins and three losses, narrowly missing the finals of the tournament.[131]

The entire Suzuki-gun returned to NJPW on January 5, 2017, attacking the Chaos stable with K.E.S. targeting IWGP Tag Team Champions Tomohiro Ishii and Toru Yano.[140][141] On February 5 at The New Beginning in Sapporo, K.E.S. unsuccessfully challenged Ishii and Yano for the IWGP Tag Team Championship in a three-way match, also involving Togi Makabe and Tomoaki Honma.[142] K.E.S. were primed for a run as NJPW's top foreign tag team, but the plan was changed when Archer was forced to undergo surgery on a herniated disc in his back.[143] Following Archer's return to NJPW in August,[144] he and Smith defeated War Machine and Guerrillas of Destiny in a three-way tornado tag team match on September 24 at Destruction in Kobe to win the IWGP Tag Team Championship for the third time.[145]

Smith was involved in a minor controversy over steroids, when, discussing how his father's drug abuse contributed to his death, Smith commented "I hope to be as big as him someday", leading to concerns over Smith using steroids.[17] Smith claimed that the remarks were taken out of context and that he had learned from his father's mistakes.[17]

On October 16, 2015, Smith announced he acquired the trademark to the "British Bulldog" moniker famously used by his father. He will now be wrestling under the name "British Bulldog" Davey Boy Smith Jr.[147]